Object moves back into origin everytime i open the blender file
there is a keyframe set on your object. That's why it moves back to original location and scales down.

You will need to open the N-Panel (see below) by hitting N and then right-click on any illumined fields and choose "Clear Keyframes"



As for not being able to apply the location, your object is a multi-user (it shares data with other objects). You will need to make it a single user by clicking the number icon here:



I hope this helps!

-Adam

EDIT: Also, if there is appears to be no keyframes set and the object still jumps back to another location, it may be controlled by an NLA strip. Open the Non Linear Animation window and delete the action that is affecting it.